When medical devices such as catheters, wire guides, cannulae, stents, and the like are introduced into the vascular system of a patient and manipulated through the vessels thereof, the blood vessel wall is commonly disturbed or injured. Clot formation or thrombosis often results at the injured site, and the blood vessel can experience obstruction or closure. Should the medical device remain within the vessel for an extended period of time, thrombus often forms on the device as well. As a result, the patient risks complications such as heart attack, pulmonary embolism, and stroke.
One medical device such as an intravascular stent provides a useful adjunct to percutaneous transluminal catheter angioplasty (PTCA), particularly in the case of acute or threatened vessel closure after an angioplasty procedure. A problem with the use of intravascular stents is that stent implantation requires aggressive and precise antiplatelet and anticoagulation therapy typically via systemic administration. Still, the incidence of thrombotic complications remains significant. Furthermore, a side effect of this systemic antiplatelet and anticoagulation therapy is increased blood loss at the percutaneous entry site where the stent is introduced into the vascular system. As a result, the incidence of bleeding complications remains significant.